PROCESS FOR PREPARING CYCLIC ANHYDRIDE FROM A LACTONE

Abstract

The present invention relates to a process for preparing cyclic anhydrides, in particular succinic anhydride and methylsuccinic anhydride, from a β-lactone, specifically β-propiolactone and β-butyrolactone, respectively, in the presence of carbon monoxide, catalyzed by dicobalt octacarbonyl [Co2(CO)8], in an organic solvent. The invention also relates to the use of this process in the manufacture of food additives, plasticizers, polymers of interest, particularly polyesters, polyurethanes, and elastanes, resins, coatings, and pharmaceuticals. Figure for the abstract: None

Description

Title of the invention: PREPARATION METHOD CYCLIC ANHYDRIDE FROM A LACTONE Technical field of the invention

[0001] The present invention relates to a process for preparing cyclic anhydride, in particular succinic anhydride and methylsuccinic anhydride, from a [3-lactone, in particular [3-propiolactone and [3-butyrolactone, respectively, in the presence of carbon monoxide, catalyzed by dicobalt octacarbonyl [Co2(CO)8], in an organic solvent.

[0002] The invention also relates to the use of this process in the manufacture of food additives, plasticizers, polymers of interest in particular polyesters, polyurethanes and elastanes, resins, coatings, pharmaceutical products. Technical background

[0003] Succinic anhydride is a molecule of industrial interest. Succinic anhydride is used as a monomer, for example, in the synthesis of aliphatic polyesters via catalytic copolymerization with an epoxide. Succinic anhydride can also be an intermediate in the synthesis of other molecules of interest: its hydration gives the corresponding diacid, succinic acid, and its dehydrogenation gives γ-butyrolactone (GBL) and then 1,4-butanediol (BDO), which can in turn be dehydrated to tetrahydrofuran (THF). These reactions are shown schematically in [Fig. 1].

[0004] To the inventors' knowledge, only two examples describe a process for synthesizing succinic anhydride by carbonylation of [3-propiolactone] in the absence of a Lewis acid additive: - The process described by Tsuji in 1969 (Y. Mori, J. Tsuji, Bull. Chem. Soc. Jpn. 1969, 42, 777. doi.org / 10.1246 / bcsj.42.777). In the presence of [Co2(CO)8] (2.5 mol%) as a catalyst, under a carbon monoxide pressure of 100 bar, in benzene, [3-propiolactone] is converted to succinic anhydride with a yield of 29%, after 4 h at 150 °C. Thus, this process gives a modest yield of succinic anhydride, even under demanding conditions, particularly with regard to pressure. - The process described by Novomer (WO2022221086) describes a method for carbonyling an epoxide or lactone by reacting it with CO in the presence of a catalyst at a temperature above 80 °C to form a carbonylation product. However, the examples given by the inventors of the present invention show that the catalytic activity is highly dependent on the choice of combination of certain reaction parameters, in particular pressure and solvent: in some cases, no catalytic activity is observed; while in others, activity is observed.

[0005] Apart from these two examples, the synthesis of succinic anhydride by carbonylation of [3-propiolactone] has only been described in the literature in the presence of a Lewis acid additive as a co-catalyst.

[0006] Any type of Lewis acid has been protected or mentioned in publications and patent applications filed by the Coates group or in patent applications filed by its company Novomer (Coates GWJ Am. Chem. Soc. 2004, 126, 6842. doi.org / 10.1021 / ja048946m; WO 03 / 050154; US 2007 / 0213524; WO 2012 / 158573; WO 2015 / 138975). This process has proven effective for the carbonylation of lactones to cyclic anhydride. The catalyst and the Lewis acid-type additive can be introduced separately or in combination as an ionic salt. The most efficient catalysts in terms of activity and / or selectivity are generally composed of an anionic carbonyl metal [Co(CO)4] and a cationic Lewis acid of the type [(ligand)M(solvent)2]+, with, for example,

[0007] M = Al or Cr;

[0008] solvent = THF,

[0009] ligand = salph, oep, tpp (salph: A,A'-bis(3,5-di-tert-butylsali-cylidenejphenyldiamino; oep: octaethylporphyrin; tpp: tetraphenylporphyrin).

[0010] These cationic Lewis acids and the corresponding catalysts may require one to several synthesis steps.

[0011] This type of Lewis acid associated with the [Co(CO)4] anion has also been described in the form of metallo-organic networks by the Dincâ and Român-Leshkov group, and this process has been shown to be effective for the carbonylation of lactones into cyclic anhydride (DP Hoyoung, M. Dincâ, Y. Român-Leshkov, J. Am. Chem. Soc. 2018,140, ​​10669. doi.org / 10.1021 / jacs.8b05948).

[0012] There is therefore a real need for a process enabling the synthesis of a cyclic anhydride in a sustainable way from reagents or solvents which can be bio-based and under relatively mild pressure and temperature conditions to reduce the energy consumption required for the synthesis of succinic anhydride.

[0013] In particular, there is a real need for a cyclic anhydride synthesis process that is easy to implement and of industrial interest.

[0014] More specifically, there is a real need for a process for synthesizing a cyclic anhydride that does not require the use of a Lewis acid-type additive. All the necessary reagents and solvents should be commercially available, without a preliminary synthesis step. Summary of the invention

[0015] The present invention is specifically aimed at meeting these needs by providing a method for preparing a cyclic anhydride of formula (I) R (I)

[0016] in which

[0017] R represents a hydrogen atom or a methyl radical, characterized in that a [3-lactone of formula (II) is reacted (II)

[0018] in which R represents a hydrogen atom or a methyl radical,

[0019] with carbon monoxide (CO), in the presence of dicobalt octacarbonyl of formula [Co2(CO)8] as a catalyst, in one or a mixture of at least two solvent(s) selected from:

[0020] - ketones, in particular, acetone, methyl ethyl ketone (MEC), methyl isobut- tyl ketone (MIBC), cyclohexanone;

[0021] - esters, in particular, ethyl acetate, methyl acetate, acetate isopropyl, butyl acetate, isobutyl acetate, isoamyl acetate, glycol diacetate, γ-valerolactone, diethyl succinate;

[0022] - ethers, in particular, tetrahydrofuran, methyltetrahydrofuran, the 1,4-dioxane, anisole, dimethoxyethane, diethyl ether, diisopropyl ether, tert-butyl methyl ether, tert-amyl methyl ether, cyclopentyl methyl ether, tert-butyl ethyl ether;

[0023] - aromatic hydrocarbons, in particular, toluene, ethylbenzene, m- and p- xylene, mesitylene, styrene;

[0024] - aprotic polar solvents, in particular, acetonitrile, N,N' - dimethylpropylene urea, dimethyl sulfoxide, sulfolane, nitromethane, dimethyl carbonate, ethylene carbonate, propylene carbonate;

[0025] at a temperature less than or equal to 150°C, and at a total carbon monoxide (CO) pressure less than or equal to 60 bar.

[0026] The conditions under which the process of the invention is implemented are particularly advantageous:

[0027] - the conditions used are mild, which helps to reduce consumption energy required for the synthesis of the product;

[0028] - an easy separation of the cyclic anhydride of formula (I) from the other species of reaction medium is possible in particular by a choice of solvent in which said cyclic anhydride has a very low solubility.

[0029] The appropriate choice of solvent and the application of carbon monoxide pressure are important parameters for implementing the process of the invention. Furthermore, the process of the invention has the advantage of avoiding the use of a Lewis acid additive.

[0030] The invention also relates to the use of this process in the manufacture of food additives, plasticizers, polymers of interest in particular polyesters, polyurethanes and elastanes, resins, coatings, pharmaceutical products. Brief description of the figures

[0031] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying figures in which:

[0032] [Fig.1] represents the use of succinic anhydride (SA) as a starting reagent for the synthesis of other molecules of industrial interest.

[0033] [Fig.2] represents the synthesis of a cyclic anhydride of formula (I) from a [3-lactone of formula (II), according to the process of the invention. Detailed description of the invention

[0034] The present invention relates to a method for preparing a cyclic anhydride of formula (I) (I)

[0035] in which

[0036] R represents a hydrogen atom or a methyl radical, characterized in that a [3-lactone of formula (II) is reacted (II)

[0037] in which R represents a hydrogen atom or a methyl radical,

[0038] with carbon monoxide (CO), in the presence of dicobalt octacarbonyl of formula [Co2(CO)8] as a catalyst, in one or a mixture of at least two solvent(s) selected from:

[0039] - ketones, in particular, acetone, methyl ethyl ketone (MEC), methyl isobut- tyl ketone (MIBC), cyclohexanone;

[0040] - esters, in particular, ethyl acetate, methyl acetate, acetate isopropyl, butyl acetate, isobutyl acetate, isoamyl acetate, glycol diacetate, γ-valerolactone, diethyl succinate;

[0041] - ethers, in particular, tetrahydrofuran (THF), methyltetrahydrofuran, the 1,4-dioxane, anisole, dimethoxyethane, diethyl ether, diisopropyl ether, tert-butyl methyl ether, tert-amyl methyl ether, cyclopentyl methyl ether, tert-butyl ethyl ether;

[0042] - aromatic hydrocarbons, in particular, toluene, ethylbenzene, m- and p- xylene, mesitylene, styrene;

[0043] - aprotic polar solvents, in particular, acetonitrile, N,N' - dimethylpropylene urea, dimethyl sulfoxide, sulfolane, nitromethane, dimethyl carbonate, ethylene carbonate, propylene carbonate;

[0044] at a temperature less than or equal to 150°C, and at a total carbon monoxide (CO) pressure less than or equal to 60 bar.

[0045] Thus, the process of the invention does not require the use of a Lewis acid-type additive. All the necessary reagents and solvents are commercially available, without any prior synthesis step.

[0046] Other advantages of the process of the invention lie in the mild conditions used which reduce the energy consumption required for the synthesis of the product.

[0047] Furthermore, solvents "recommended" with regard to their safety, toxicity, and environmental impact can be used in the process of the invention (Prat, D., Wells, A., Hayler, J., Sneddon, H., McElroy, CR, Abou-Shehada, S., & Dunn, PJ Green Chemistry, 2016,18, 288; doi.org / 10.1039 / C5GC01008J).

[0048] Variants of the process of the invention consist in the choice of solvent, carbon monoxide pressure, reaction temperature, reaction time, initial lactone concentration and catalytic charge.

[0049] In a preferred embodiment of the invention, the solvent or mixture of at least two solvent(s) is / are chosen from:

[0050] - acetone;

[0051] - ethyl acetate;

[0052] - 1,4-dioxane;

[0053] - tetrahydrofuran (THF);

[0054] - anisole;

[0055] - dimethoxyethane;

[0056] - acetonitrile;

[0057] - dimethyl carbonate;

[0058] - ethylene carbonate;

[0059] - propylene carbonate; and

[0060] - toluene.

[0061] In another preferred embodiment of the invention, the solvent or mixture of at least two solvent(s) is / are chosen from:

[0062] - acetone;

[0063] - ethyl acetate;

[0064] - 1,4-dioxane;

[0065] - tetrahydrofuran (THF);

[0066] - anisole;

[0067] - dimethoxyethane;

[0068] - acetonitrile;

[0069] - dimethyl carbonate;

[0070] - toluene.

[0071] In another preferred embodiment of the invention, the solvent is acetonitrile.

[0072] The total carbon monoxide pressure can vary from 1 bar to 60 bar depending on the solvent, the catalytic charge, the reaction temperature, the lactone concentration, and the desired reaction time.

[0073] In one embodiment of the invention, the process of the invention occurs under a total carbon monoxide (CO) pressure of 1 to 60 bar.

[0074] In a preferred embodiment of the invention, the process of the invention occurs under a total carbon monoxide (CO) pressure of 5 to 50 bar. In another preferred embodiment of the invention, the total carbon monoxide (CO) pressure is 5 to 20 bar.

[0075] The reaction temperature can vary from 30 °C to 150 °C depending on the solvent, the catalytic charge, the lactone concentration and the desired reaction time.

[0076] In a preferred embodiment of the invention, the temperature is between 60 and 150°C. In another preferred embodiment of the invention, the temperature is between 60 and 130°C. According to another preferred embodiment of the invention, the temperature is between 90 and 130°C. According to another preferred embodiment of the invention, the temperature is between 90 and 110°C.

[0077] In the process of the invention, the amount of dicobalt octacarbonyl of formula [Co2(CO)8], as a catalyst, is 0.1 to 10 mol%, preferably 0.5 to 8 mol%, more preferably 1 to 6 mol%, relative to the amount of lactone of formula (II). Increasing the amount of the catalyst reduces the reaction time.

[0078] The concentration of lactone of formula (II) as defined above can vary from several mmol.L⁻¹ to several mol.L⁻¹*. According to one embodiment of the invention, the concentration of lactone of formula (II) is from 0.01 to 6 M. According to a preferred embodiment of the invention, the concentration of lactone of formula (II) is between 0.1 and 2 M. According to a further preferred embodiment of the invention, the concentration of lactone of formula (II) is between 0.25 and 1 M.

[0079] The reaction time can vary from a few minutes to a few days depending on the lactone, the solvent, the catalytic charge, the lactone concentration, and the temperature. The duration of the process of the invention is between 30 minutes and 150 hours. Preferably, the duration is between 6 and 110 hours.

[0080] In one embodiment of the invention, R represents a hydrogen atom.

[0081] In another embodiment of the invention, R represents a methyl radical.

[0082] When R represents a hydrogen atom, the cyclic anhydride of formula (I) is succinic anhydride and the lactone of formula (II) is [3-propiolactone].

[0083] Where R represents a methyl radical, the cyclic anhydride of formula (I) is succinic methyl anhydride and the lactone of formula (II) is [3-butyrolactone.

[0084] Moreover, the process of the invention is intended to be easily applied at the industrial level and to be competitive with the processes already implemented on an industrial scale, since it uses dicobalt octacarbonyl [Co2(CO)8], already proven in industrial hydroformylation processes, which can be used here under relatively mild pressure and temperature conditions (such as, for example, 60 bar or less and 150°C or less).

[0085] Unlike known processes, the process of the invention does not require the addition of an additional additive to improve the performance of the process.

[0086] In the context of the invention, "additive" means a compound which is a Lewis acid, suitable for improving the reactivity of the reagents for the transformation of the lactone of formula (II) into a cyclic anhydride of formula (I).

[0087] Furthermore, another advantage of the process of the invention is the simplicity of its implementation: in addition to the absence of Lewis acid additives, the dicobalt octacarbonyl [Co2 (CO)8] and the solvent(s) are commercial products and therefore do not require of an additional synthesis step. The process is effective at low pressure, in particular, less than and equal to 60 bar, which is particularly advantageous from an industrial point of view.

[0088] The invention also relates to the use of this process in the manufacture of food additives, plasticizers, polymers of interest in particular polyesters, polyurethanes and elastanes, resins, coatings, pharmaceutical products. Experimental description of the invention:

[0089] The various reagents, catalysts, additives and solvents used directly or indirectly in the process of the invention in particular are, in general, commercial compounds / solvents.

[0090] Another object of the invention is the use of a process according to the invention, in the manufacture of food additives, plasticizers, polymers of interest in particular polyesters, polyurethanes and elastanes, resins, coatings, pharmaceutical products.

[0091] The process for manufacturing food additives, plasticizers, polymers of interest in particular polyesters, polyurethanes and elastanes, resins, coatings, pharmaceutical products, may include a step of preparing a cyclic anhydride of formula (I), in particular succinic anhydride, by the process of the invention. EXAMPLES

[0092] The various reagents and solvents used in the process of the invention and in the examples are, in general, commercial compounds or can be prepared by any process known to a person skilled in the art.

[0093] Unless otherwise specified, all reactions were carried out under argon, in an anhydrous and inert atmosphere (< 5 ppm H2O and O2) using conventional Schlenk techniques with a vacuum manifold or in a glove box (mBraun LabMaster DP). The glassware was dried for several hours at 120°C in an oven before use. The reaction solvents were pre-dried by standard methods, distilled, and stored in an inert atmosphere on 4 Å molecular sieve. The 4 Å molecular sieve (Aldrich) was pre-dried under dynamic vacuum at 250°C for 48 h before use. All products were purchased from standard suppliers (Sigma Aldrich, Strem, Alfa-Aesar, Acros, etc.) and pre-dried or degassed as necessary. The carbon monoxide was obtained from 4.7 purity pressurized cylinders from Air Products.

[0094] The synthesized compounds were characterized and quantified by analytical and mass spectrometry techniques using the Shimadzu GCMS QP2010 instrument Ultra, equipped with a Supelco SLB-ms silica column (30 m x 0.25 mm x 0.25 pm). The carrier gas is Messer helium (purity 6.0). The products were identified by comparison with commercial standards and calibrated using mesitylene as an internal standard. Experimental protocol:

[0095] 1. Under an inert atmosphere, dicobalt octacarbonyl [Co2(CO)8] is dissolved in the solvent. Depending on the solvent used, gas evolution may be observed. The lactone is then added. In order to monitor the cyclic anhydride yield and lactone conversion, an internal standard such as mesitylene may be added. 2. The reaction mixture is introduced into an autoclave that has been previously purged three times with a stream of carbon monoxide. The autoclave contains a glass tube to collect the reaction mixture and is equipped with a magnetic stirrer. 3. The autoclave is then sealed, and carbon monoxide is injected into the autoclave until the desired total pressure is reached. 4. The autoclave is placed in a heating block under magnetic stirring. 5. The reaction is stopped by immersing the autoclave in an ice bath. 6. Once the autoclave is at room temperature (20 ± 5°C), it can be opened, and the reaction mixture can be analyzed.

[0096] The conversions and yields described are measured by GC-MS (Gas Chromatography - Mass Spectrum) using an internal standard added at the beginning of the reaction, mesitylene, for which a calibration curve has been previously established. Example 1:

[0097] Dicobalt octacarbonyl (17.1 mg; 0.05 mmol; 0.05 eq) is dissolved in acetonitrile (2 mL). Gas evolution is observed and lasts approximately 20 min. Mesitylene (14 pL; 0.1 mmol; 0.1 eq) and 3-propiolactone (63 pL; 1 mmol; 1 eq) are then added to the reaction mixture. The reaction mixture is introduced into the autoclave, which has been purged three times with a stream of carbon monoxide. The autoclave is sealed and subjected to a carbon monoxide pressure of 15 bar, then placed under magnetic stirring for 6 h in a heating block at 90 °C. After analysis of a crude reaction sample by GC-MS, 100% of the [3-propiolactone] was converted, for a succinic anhydride yield of 99%. Example 2:

[0098] Dicobalt octacarbonyl (17.1 mg; 0.05 mmol; 0.05 eq) is dissolved in acetonitrile (2 mL). Gas evolution is observed and lasts approximately 20 min. Mesitylene (14 pL; 0.1 mmol; 0.1 eq) and [3-butyrolactone (86.1 mg; 1 mmol; 1 eq) are then added to the reaction mixture. The reaction mixture is introduced into the autoclave, which has been purged three times with a stream of carbon monoxide. The autoclave is sealed and subjected to a pressure of 15 bar of carbon monoxide, then placed under magnetic stirring for 39 h in a heating block at 110 °C. After analysis of a crude reaction sample by GC-MS, 87% of the [3-butyrolactone] was converted, yielding 67% methylsuccinic anhydride. Tests performed:

[0099] The cyclic anhydride yield and lactone conversion were obtained by GC-MS, following calibration with commercial samples of cyclic anhydride and lactone. The percentage values ​​are given with an uncertainty of + / - 5 percentage points.

[0100] For the carbonylation of [3-propiolactone] to succinic anhydride (Table 1), it is noted that: - In acetone, 1,4-dioxane, toluene, anisole, dimethyl carbonate, and ethyl acetate, a decrease in pressure leads to an increase in yield (Table 1, entries 1-7 and 24-35). In particular, increasing the pressure to 50 bar induces a loss of activity in 1,4-dioxane, anisole, and dimethyl carbonate (Table 1, entries 7, 29, and 32), and this loss of activity is observed even at 15 bar in toluene (Table 1, entries 25 and 26). - In dimethoxyethane, pressure has no influence on yield (Table 1, entries 8-10). - DMF is an unsuitable solvent for the process, regardless of the pressure tested (Table 1, entries 11-13). - In acetonitrile and THF, increasing the pressure from 5 to 15 bar leads to an increase in yield, but increasing it from 15 to 50 bar leads to a decrease in yield (Table 1, entries 14-17 and 21-23). ​​For these two solvents, a moderate pressure is therefore preferable. - The optimal conditions for the process consist of using acetonitrile as the solvent, at a pressure of 15 bar, where a quantitative yield of anhydride is observed after 6 h (Table 1, entry 16).

[0101] The results of the different experiments have been compiled in the following tables. Anhydride 05 t. ?

[0102] [Tables 1] Solvent Input TfC) P (bar) UN Succinic anhydride Yield (%) 1 Acetone 90 5 6 77 2 Acetone 90 15 6 57 3 Acetone 90 15 15 79 4 Acetone 90 50 6 29 5 1,4-dioxane 90 5 6 76 6 1,4-dioxane 90 15 6 38 7 1;4-Dioxane 90 50 6 < O 8 Dimethoxyethane 90 5 6 74 9 Dimethoxyethane 90 15 6 76 10 Dimethoxyethane 90 50 6 71 11 A-methylformamide 90 5 6 < O 12 W-methylformamide 90 15 6 O 13 M-dimethylformamide 90 50 s < 5 14 Acetonitrile 90 5 6 73 15 Acetonitrile 90 15 3 92 16 Acetonitrile 90 15 6 99 17 Acetonitrile 90 50 6 38 18 Acetonitrile 11G 15 1 83 19 Acetonitrile 110 15 3 87 20 Acetonitrile 130 15 1 65 21 Tetrahydrofuran 90 5 6 69 22 Tetrahydrofuran 90 15 6 83 23 Tetrahydrofuran 90 50 6 58 24 Toluene 90 5 6 44 25 Toluene 90 15 6 < 5 26 Toluene 90 50 6 < 5 27 Anisole 90 5 6 38 28 Anisole 90 15 6 13 29 Anisole 90 50 6 < 5 30 Dimethium Carbonate 90 5 6 51 31 Dimethium Carbonate 90 15 6 13 32 Dimethium Carbonate 90 50 6 < 5 33 Ethyl acetate 90 5 6 76 34 Ethyl acetate 90 15 6 37 35 Ethyl acetate 90 50 6 16 36* Acetonitrile 90 15 18 92 37* Acetonitrile 90 15 72 60 ; ■' : 2:5 moi% of [Co2(CO)s] are used. * : 1 mol% of [Co?(CO}a] is used.

[0103] Table 1 - Carbonylation of p-propiolactone to succinic anhydride.

[0104] For the carbonylation of [3-butyrolactone] to methylsuccinic anhydride (Table 2), it is noted that:

[0105] - at 90 °C, little activity is observed (Table 2, entry 1).

[0106] - increasing the temperature to 110 or 130 °C allows the formation to be observed of the anhydride, but a temperature of 110 °C is preferable for better yield (Table 2, entries 2-4).

[0107] - increasing the pressure to 50 bar causes a decrease in efficiency (Table 2, entries 5 and 6). Q 5 wi L rnéthyisucdn^e

[0108] [Tables2] Input _ — "EP (bar) __ wt rq __ 110 Hh) 16 Methylfire yield <5 48 ni in eeiniqu® anhydride (%) 15 110 39 67 4 15 130 39 38 5 50 ÏÏ0 16 31 6 50 110 72 34

[0109] Table 2 - Carbonylation of p-butyrolactone to methylsuccinic anhydride.

[0110] The tests carried out by the inventors in the laboratory show that the combination of certain parameters does not allow for a yield of more than 5% of succinic anhydride or methylsuccinic anhydride. In other words, the combination of certain parameters results in only very weak or no catalytic activity (Table 1, Table 2). More specifically, the inventors observed very weak catalytic activity in the following cases, using [Co2(CO)8] as a catalyst for the carbonylation of [3-propiolactone], after heating at 90 °C for 6 h (Table 1):

[0111] - in 1,4-dioxane, at 50 bar (Table 1, entry 7);

[0112] - in dimethyl carbonate, at 50 bar (Table 1, entry 32);

[0113] - in A,A-dimethylformamide, at 5, 15 and 50 bar (Table 1, entries 11 to 13);

[0114] - in toluene, at 15 and 50 bar (Table 1, entries 24 and 25).

[0115] Similarly, for the carbonylation of [3-butyrolactone, catalyzed by [Co2(CO)8] in acetonitrile at 15 bar, very low activity was observed after 6 h at 90 °C (Table 2, entry 1).

[0116] Conversely, the inventors have shown that a judicious combination of parameters allows for the observation of high catalytic activity. This is illustrated by the other catalytic tests described for the carbonylation of [3-propiolactone] in Table 1:

[0117] - acetone and ethyl acetate allow good yields to be obtained in succinic anhydride at all pressures, but especially at low pressure (77% and 76% at 5 bar, Table 1, entries 1 and 33);

[0118] - 1,4-dioxane, anisole and dimethyl carbonate make it possible to obtain a moderate or good yield, at low or moderate pressure (13 to 76%, Table 1, entries 5, 6, 27, 28, 30 and 31);

[0119] - Dimethoxyethane allows for good efficiency at all pressures (71 to 76%, Table 1, entries 8 to 10);

[0120] - acetonitrile allows for moderate to very good performance at any pressure (38 at 99%, Table 1, entries 14 to 20); in particular, a quantitative yield of succinic anhydride is observed under 15 bar of carbon monoxide, after 6 h of reaction at 90 °C (Table 1, entry 16);

[0121] - Tetrahydrofuran allows for moderate to very good yield at all pressure (58 to 83%, Table 1, inputs 21 to 23); the highest efficiency is observed at 15 bar (83%, Table 1, input 22);

[0122] - toluene allows for a moderate yield at low pressure (44%, Table 1, entry 24).

[0123] These catalytic results illustrate that the combinations of the two parameters "solvent" and "pressure" are not obvious, since no clear and systematic trend emerges. Some solvents are not effective at any pressure (N,N-dimethylformamide), others are effective at any pressure (dimethoxyethane), others are more effective as the pressure is lower (acetone, 1,4-dioxane, toluene, anisole, dimethyl carbonate, ethyl acetate), and others are more effective at moderate pressure (acetonitrile, tetrahydrofuran).

Claims

Claims

1. Process for the preparation of a cyclic anhydride of formula (I) R (I) in which R represents a hydrogen atom or a methyl radical, characterized in that a [3-lactone of formula (II)] is reacted R (II) in which R represents a hydrogen atom or a methyl radical, with carbon monoxide (CO), in the presence of dicobalt octacarbonyl of formula [Co2(CO)8] as catalyst, in one or a mixture of at least two solvent(s) chosen from: - ketones, in particular, acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBC), cyclohexanone; - esters, in particular, ethyl acetate, methyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, glycol diacetate, y-valerolactone, diethyl succinate; - ethers, in particular tetrahydrofuran (THF), methyltetrahydrofuran, 1,4-dioxane, anisole, dimethoxyethane, diethyl ether, diisopropyl ether, methyl tert-butyl ether, methyl tert-amyl ether, methyl cyclopentyl ether, ethyl tert-butyl ether; - aromatic hydrocarbons, in particular, toluene, ethylbenzene, m- and p-xylene, mesitylene, styrene; - aprotic polar solvents, in particular, acetonitrile, N,N'-dimethylpropylene urea, dimethyl sulfoxide, sulfolane, nitromethane, dimethyl carbonate, ethylene carbonate, propylene carbonate; at a temperature less than or equal to 150°C, and at a total pressure in carbon monoxide (CO) less than or equal to 60 bar.

2. Process according to claim 1, characterized in that the or the mixture of at least two solvent(s) is chosen from: - acetone; - ethyl acetate; - 1,4-dioxane; - tetrahydrofuran (THF); - anisole; - dimethoxyethane; - acetonitrile; - dimethyl carbonate; and - toluene.

3. Method according to one of claims 1 or 2, characterized in that the solvent is acetonitrile.

4. Method according to any one of claims 1 to 3, characterized in that it occurs under a total carbon monoxide (CO) pressure of 1 to 60 bar.

5. Method according to any one of claims 1 to 4, characterized in that it occurs at a temperature between 30 and 150°C.

6. Process according to any one of claims 1 to 5, characterized in that the amount of dicobalt octacarbonyl of formula [Co2(CO)8], is 0.1 to 10 mol%, relative to the amount of lactone of formula (II).

7. Process according to any one of claims 1 to 6, characterized in that the concentration of lactone of formula (II) is 0.01 to 6 M.

8. Method according to any one of claims 1 to 7, characterized in that the duration of the method is between 30 minutes and 150 hours.

9. Method according to any one of claims 1 to 8, characterized in that R represents a hydrogen atom.

10. Process according to any one of claims 1 to 8, characterized in that R represents a methyl radical.

11. Use of a process according to any one of claims 1 to 10, in the manufacture of food additives, plasticizers, polymers of interest, in particular polyesters, polyurethanes and elastanes, resins, coatings, pharmaceutical products.